The present invention relates to a laparoscopic instrument, and more particularly to a laparoscopic instrument having a manually operable tip, such as cutting blades, forceps, or the like, and to a removable shaft therefor.
A wide variety of medical instruments for laparoscopic surgery are presently known. Such instruments are used to access, e.g., the peritoneal cavity of a patient through a small incision in the abdominal wall. An endoscope normally is inserted into the cavity through a second incision in the abdominal wall for viewing of the operation of the instrument by the surgeon. Typical of such laparoscopic instruments are those having a tip end including, e.g., cutting blades, forceps, or other surgical device to be inserted into the cavity to perform the surgery; an external end from which the surgeon may manually manipulate the tip device from a position external to the abdominal wall; and an elongated shaft operably connecting the tip end and the external end. Many such laparoscopic instruments have permanently attached tips. However, in recent years instruments have been developed having disposable tips. Thus, a worn cutting blade may be replaced or one type of tip may be replaced with another, interchangeable type.
Because of the high cost of such laparoscopic instruments, reuse of each instrument, or part of each instrument, would be advantageous in controlling the cost of laparoscopic surgery. However, such reuse requires instruments of rugged construction which may be readily cleaned and sterilized. Known laparoscopic instruments, even those with removable tips, can be difficult to clean due to their length and complex internal structure.
Above-referenced Pat. No. 5,810,879 describes a laparoscopic instrument assembly in which the shaft and the body of the assembly may be readily disassembled. The shaft between the tip and the externally manipulable body of the instrument includes a rod moving axially within a sheath to transmit the manipulation of a tip actuating mechanism within the body to actuate the tip. The sheath is removable from the body for cleaning of the instrument, i.e., after use of the instrument, the shaft may be readily disassembled from the body, the shaft and body sterilized, and the shaft and body readily reassembled for reuse of the instrument. Alternatively, the shaft may be disposed of and the body reassembled with a fresh shaft. The assembly may be used with a removable tip provided separately, or a removable or non-removable tip may be provided as part of the assembly. In this type of instrument, the tubular sheath is secured within the body by compression applied by the action of a collet closer on a collet within the body. It would be desirable, however, to provide additional securing means for improved retention and stabilization of the sheath within the collet during operation of the instrument.
Accordingly, it is an object of the present invention to provide a laparoscopic instrument which overcomes the disadvantages of the prior art.
It is another object of the invention to provide a laparoscopic instrument assembly, including additional sheath securing means, which is easily and thoroughly cleaned by normal hospital equipment and procedures.
It is yet another object of the invention to provide a laparoscopic instrument assembly, including additional sheath securing means, in which the shaft and body of the instrument are readily disassembled for cleaning and reassembled for reuse.
It is yet another object of the invention to provide a shaft for a laparoscopic instrument, including means for securing the sheath within the body of the instrument.
In accordance with these objects, in one aspect the invention is a laparoscopic instrument assembly including a handle member or body, an elongated shaft operably and removably gripped by the body and extending from the body to interconnect the body with a surgical tip, and, optionally, a removable or non-removable surgical tip.
The body includes a casing, manually manipulable tip actuating means, and a tip actuating rod, and also includes a collet and a collet closer each coaxial with an axial bore through the casing. The body further includes one or more collet detent members, e.g., balls, to secure a sheath portion of the shaft within the body, as described below.
The shaft extends from the body to interconnect the body with a tip, and includes a tubular sheath and a rod having a body end and a tip end. The shaft rod is movable axially within the sheath in response to movement of the tip actuating rod by the tip actuating means to transmit manipulation of the tip actuating means to actuate the surgical tip. The sheath also has a body end and a tip end. An external surface of the sheath includes at the body end thereof at least one detent member-receiving depression, e.g., a groove to receive the collet detent members. One or both of the tip actuating rod and the shaft rod include means for operably and removably connecting the shaft rod to the tip actuating rod.
The collet includes an axial bore therethrough dimensioned for close sliding fit about the sheath and one or more radial bores extending radially through the collet from an outer surface thereof to be open to the axial bore. The collet radial bores are of a first, larger diameter at the collet outer surface and a second, smaller diameter at an opening of the collet radial bores into the collet axial bore.
The collet closer is shaped and sized to, on tightening of the collet closer, radially compress the collet to grip the sheath. Each collet detent member is disposed in one of the collet radial bores. Each collet detent member is shaped and sized to (a) permit only partial entry of the collet detent member into the collet axial bore to engage the sheath depression during assembly of the instrument assembly, and (b) be freely movable radially within its collet radial bore in response to urging inwardly by an internal surface of the collet closer as it is tightened during assembling of the instrument assembly, or outwardly by a wall of the sheath depression when the collet closer is loosened during disassembling of the instrument assembly.
In a narrower embodiment, the laparoscopic instrument assembly further includes the surgical tip, which may be removable or non-removable from the shaft. In another narrower embodiment, the collet and collet closer are each coaxial with the casing axial bore.
In another aspect, the invention is a body for a laparoscopic instrument including a body and an elongated shaft gripped by the body and extending from the body to interconnect the body with a surgical tip. The body includes a casing, manually manipulable tip actuating means, a tip actuating rod including means for operably and removably connecting a shaft rod of the shaft to the tip actuating rod.
The body further includes a collet, a collet closer, and one or more collet detent means. The collet includes an axial bore therethrough dimensioned for close sliding fit about a sheath of the shaft and one or more radial bores extending radially through the collet from an outer surface thereof to be open to the axial bore. The collet radial bores are of a first, larger diameter at the collet outer surface and a second, smaller diameter at an opening of the collet radial bores into the collet axial bore. The collet closer is shaped and sized to, on tightening of the collet closer, radially compress the collet to grip the sheath. The one or more collet detent members are each disposed in one of the collet radial bores. Each collet detent member is shaped and sized to (a) permit only partial entry of the collet detent member into the collet axial bore to engage a depression on the shaft sheath during-assembly of the instrument assembly, and (b) be freely movable radially within its collet radial bore in response to urging inwardly by an internal surface of the collet closer as it is tightened during assembling of the instrument assembly, or outwardly by a wall of the sheath depression when the collet closer is loosened during disassembling of the instrument assembly.
In yet another aspect, the invention is an elongated shaft for a laparoscopic instrument including a body having a tip actuating rod, the shaft being gripped within the instrument by the body to extend from the body to interconnect the body with a surgical tip. The shaft includes a tubular sheath having a body end and a tip end. An external surface of the sheath includes at the body end thereof at least one detent member-receiving depression, e.g., a groove. The shaft further includes a rod axially moveable within the sheath. The shaft rod has a body end and a tip end, and includes means at the rod body end for operably and removably connecting the shaft rod to the tip actuating rod. In a narrower embodiment, the shaft further includes the surgical tip, the surgical tip being removable or non-removable from the shaft.